476 TRANSACTIONS OF THE 



phate of lime for its base, indurated by a solution of boron (the base of 

 boracic acid — from borax, the salt found native in the lakes in Thibet and 

 Persia, and is imported from India, by the name of Fhical, which is 

 refined and forms our borax.) 



This boron can be so varied in quantity in the plaster, that the plaster 

 may be made to set in a feio 77iovie?its, or in some hours, as may be 

 required. It makes the plaster very hard, resembling marble or stone. 

 It has considerable strength — is believed to be for columns as strong as 

 freestone. Its surface is fit for paint almost immediately. 



NEW METHOD OF ROAD MAKING. 



France has it on a part of the Place du Palais Royal, a concrete about 

 Jive inches thick, is first spread out. On that a layer of bitumen powdered 

 and boiling hot, is poured on about_^re inches thick. A quantity of river 

 sand is sifted over that, and rolled in by a cast iron roller of about two 

 tons weight. In a few hours this road maybe passed over by the heaviest 

 wagons, without the slightest impression being left by the wheels. It has 

 been applied to the Rue St. Honore, between the Palais Royal and the 

 Rue de Richelieu, and as far as the end of the Theatre Francais. 



OAK PAPER. 



John Stather, of Hull, prints paper from the oak itself, surpassing any 

 painting. By taking off shaving after shaving, he obtains continual varie- 

 ties of the shades and grain of the oak. 



XYLOPLASTY. 



Paris does it. The wood is softened by steam, then imbued with cer- 

 tain ingredients, giving it sufficient ductility to receive impressions from 

 four to five millimetres deep (about three eighths of an inch.) 



WATER PROOF PAPER. 



Professor Muschamp, of Wurtemberg, uses twenty-four ounces of alum 

 and four ounces of white soap ; he dissolves these in two pounds of water. 

 In another vessel, he dissolves two ounces of gum arable and six ounces of 

 glue in two pounds of water. Add the solutions together ; keep warm. 

 Dip paper into it and then pass it between rollers and dry it — or without 

 the rollers — hang it up to dry. The alum, soap, glue and gum, form an 

 artificial leather, and it is somewhat fire-proof. 



Paper dipped in diluted oil of vitriol and immediately well washed in 

 pure water, render paper strong and somewhat water-proof. 



Alanson Nash remarked, in relation to the last subject before the Poly- 

 technic — the building materials of the State of New York — that we pos- 

 sessed masses of Basaltic green stone on Long Island, and in "Westchester, 

 It is exceedingly hard, splits into plates, forms elegant walls, is siliceous, 

 with coloring from copper, is a sort of lava, hove up at the time when that 

 great crack through our State, now occupied by the Hudson river. The 

 Palisade rocks, of which on the right bank show it partially columnae and 

 chrystallic. Above the Highlands of the Hudson river, the great basin, 



